In a digital video signal processing system, the line-locked synchronizing signals serve as reference signals for non-standard video signals such as signals of a video tape recorder. Burst-locked signals serve as reference signals for standard video signals such as broadcasting signals satisfying 1, he following formula, EQU fsc=(455/2).times.(525/2).times.fv,
In the formula, fsc represents the frequency of the burst signal, and fv represents the frequency of the vertical synchronizing signal.
Conventionally, in the digital video processing system for processing standard video signals in which burst-locked signals such as broadcasting signals serve as the reference signals, burst-locked signals are used to prevent errors from occurring during comb-filtering such as when performing 3-dimensional Y/C separation.
However, the burst-locked signals serving as the reference signals for performing the comb-filtering have to be converted to line-locked signals by a sample ratio converting circuit, because line-locked signals ultimately serve as the reference signals for Y/C processing or Y/C interpolation circuits. As a result, the system is increased in size due to the addition of the sample ratio converting circuit.